Arc-lamp electrode.



.15 the paint industry, called lithopone which p t ssi m r on Th fl mi g70! nninn same Parana onnrc.

WILLIAM R. MOIT, or LAKEWOQD, OHIO, assrsnon, BY mnsnn ASSIGNMENTS, TGnarrower. cannon corarsitx, two, A eonronariou on NEW YORK.

ARC-LAMP ELECTRODE.

1 239,8}1 Specification of Letters Patent. Patented Sept, 11, 116331 7,No Drawing. Application filed. January 4, 1916. Serial No. 70,251. Toall whom it may concern: of excessive slagging. On the other hand,

Be it known that I, WILLIAM R. Mora, a only slight benefits will beobtained with cltlzen of the Un'ted States, residing at smallpercentages of lithopone, say 1 or 2%. Lakewood, in the county ofGuyahoga and As a general proposition, it is best to use 5 State ofOhio, have invented a certain new he lithopone in quantities equal toabou so and useful Improvement in Arc-Lamp Elec- 4% to 16% of the entireflaming material trodes, of which the following is a full, in theelectrode. clear, and exact description. As a specific illustration ofan electrode Thlsv invention relates to are lamp elecwhich I have foundto give satisfactory retrodes and consists in the employment of suits, Imay men ion the following, bu n y 65 novel combinations thatbeneficially affect by Way of example. A solid flame carbon the flamingproperties when used in the pro- 1s made with a flame mix consisting of19% duction of light. calcium fiuorid, 8% calcium sulfate. 60%

There is a ompound extengively used in rare-earth flLlOl'lClS, 8%lithopone and 5% has the formula 5x530 2118. This material terials andthe carbon flour would of course Ihave found t hav new nd u ful m. firstbe mixed with some binder, such as tions in a flame carbon. It is verysuitable t r, pitch, and oils, in the usual proportions,

for arc lamp electrodes, as it' serves as an that is, a out 15% to ofthe aggregate 20 excellent flux for calcium fluorids and other of e o hr n it ent In g n ral, i i fiuorids,'by preventing them from forming,advisableto use about to (50% of flame s ag beads on the end of theelectrode, that material mixed with 70% to 40% of carbon would preventthe lamp from picking up. material. These homogeneous carbons. are

The favorable action of lithopone, as re forced and baked in the usualway, well 25 gards slaggin'g, is partly due to it decreasknown in theart of carbon manufacture. so

- ing the surface tension between the flame I have also found that goodresults are mixture and the carbon and hence causes an obtained with 19%calcium fiuorid, 16% increased tendency of the molten flame mix, calciumsulfate, 52% rare-earth fluorids, 8% near the hot crater of the arc, towet the carlithopone and 5% potassium carbonates.

- 30 bong b tt r tha wh al iu fiu rid r This material would be mixedwith carbon "t0 the fact that barium sulfate (one of the NdFpraeseodymium fiuorid PrF lantha- 5 other fluorid is used alone. and abinder in the same way as is men- This complex compound also increasesthe tioned in the first example. In place of the candle power and whit ns (due to blue potassium carbonate, good results can be green and bluespectral nature of light of obtained by using a mixture of potassium35barium compounds and zinc) and it praccarbonate, calcined potassiumsilicate and tically eliminates-the etching of the lamp potassiumchlorid.

globes which is caused by the fluorin vapor- I have mentioned calciumfluorid and ous compounds from the arc. It also marare-earth fiuorids(made up chiefly of terially increases the life, which is due to eriumfluorid Gel? neodymium fluorid constituents of lithopone). is reformedat num fluorid La F and yttrium fiuorid YtF the cooler regions of theare after having as the fiuorid materials to be incorporated beendecomposed in the hotter portions. in the electrode, as these are themost satis- Thus substantially no free oxygen is elimifactory and theones most generally used. d5 nated from this compound to cause the un-However, other fiuorids may be used, such due combustion of the carbonelectrodes. as magnesium fiuorid MgF strontium There is no exactmathematical propo'rfiuorid SrF barium fluorid BaF uranium tion to beadhered to,'but I find that the fluorid UrF ,'zirconii1m fluorid ZrFetc., ratio of lithopone to the combined fluorid as well as doublefluorids such as cryolite, fit) content should be within certain limits.For potassium zirconium fiuorid, sodium ura- I05 example, with 90 to 70parts of calcium nium double fluorid, etc. While I do not fiuorid andrare-earth fluorids, there should know that lithopone could be used withany be 5 to'30 parts lithopone to get the best and all fluoride, itapparently could if such results. The percentage of lithopone shouldfluoride themsekves did' notfhave inherent I 65 not be carried aboveabout 50% on account def'e'ctsthat would otherwise preventthe'ir [11obeing used Withthe materials mentioned herein, and the term fluorids inthe claims is intended to cover those mentioned, and also others thatare as a matter of fact, equivalents of the same.

The above invention has been described in connection with solidhomogeneous electrodes, but it is not necessarily limited thereto. Itcould also be used with cored' carbons. As is usual in manufacturingcored electrodes, the flaming paste Would be squirted into carbon shellsand dried at a moderate temperature to set the binder.

The exact ratio of barium sulfate to zinc sulfid in lithopone may varyconsiderably from the formula previously given herein. In fact,lithopone' is a trade .term intended to designate a product obtained bythe simultaneous precipitation of barium sulfate and zinc sulfid,regardless of the exact constitution. All such variations are. ac-

v cordingly Within the scope of my invention.v Having described myinvention, Whatff claim is 1. An are lamp electrode containing pone.

2. An a c lamp electrode containing a" WILIAM R. M TT.

